package com.itheima.filter;

import com.alibaba.fastjson.JSON;
import com.itheima.common.BaseContext;
import com.itheima.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 检查用户是否已经完成登录
 */
@Slf4j
//先拦截所有路径，然后再处理需要放行的请求路径
@WebFilter(filterName = "loginCheckFilter", urlPatterns = "/*")
public class LoginCheckFilter implements Filter {

    //路径匹配器，支持通配符
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        //1.获取本次请求的URI
        //URI：要求找到一本书（书就是资源），这本书在A省份/B市/C区/D街道/xx栋/392-1住户/1号房间/名字叫做《xxx》 (这里就是模拟我们输入网址进行HTTP请求)
        //那么此时的 《xxx》 这本书 对于 1号房间 来说就是uri
        //此时的D街道/xx栋/392-1住户/1号房间/名字叫做《xxx》这本书 对于 A省份/B市/C区 来说就是uri
        String requestURI = request.getRequestURI();
        log.info("拦截到请求：{}", requestURI);
        //定义一个String类型的数组，来存放不需要处理的请求路径
        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**",
                "/common/**",
                "/user/sendMsg",    //移动端发送短信
                "/user/login",       //移动端登录
                "/doc.html",
                "/webjars/**",
                "/swagger-resources",
                "/v2/api-docs"
        };
        //2.判断本次请求是否需要处理
        boolean result = check(urls, requestURI);
        //3.如果不需要处理则直接放行
        if (result) {
            log.info("本次请求{}不需要处理", requestURI);
            filterChain.doFilter(request, response);
            return;
        }
        //4-1.后台：如果需要处理，则需要判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("employeeId") != null) {
            log.info("用户已登录，用户id为：{}", request.getSession().getAttribute("employeeId"));

            //把员工id设置进ThreadLocal中
            Long empId = (Long) request.getSession().getAttribute("employeeId");
            BaseContext.setCurrentId(empId);

            filterChain.doFilter(request, response);
            return;
        }

        //4-2.前台：如果需要处理，则需要判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("userId") != null) {
            log.info("用户已登录，用户id为：{}", request.getSession().getAttribute("userId"));

            //把员工id设置进ThreadLocal中
            Long userId = (Long) request.getSession().getAttribute("userId");
            BaseContext.setCurrentId(userId);

            filterChain.doFilter(request, response);
            return;
        }

        log.info("用户未登录");
        //5.如果未登录，则返回未登录状态。通过输出流方式向客户端页面响应数据
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        return;

    }

    /**
     * 路径匹配：检查本次路径是否需要放行
     *
     * @param urls
     * @param requestURI
     * @return
     */
    public boolean check(String[] urls, String requestURI) {
        for (String url : urls) {
            boolean result = PATH_MATCHER.match(url, requestURI);
            if (result) {
                return true;
            }
        }
        return false;
    }

}
